The Pharmaceutical Benefits Advisory Committee (PBAC) refused to approve the drug used in HIV pre-exposure prophylaxis (PrEP), Tenofovir (better known by its brand name, Truvada) for the PBS, instead requesting more information from the drug's sponsor and production companies in Australia, Gilead Sciences and Mylan Australia, before moving forward.

"The PBAC deferred making a recommendation on tenofovir with emtricitabine for HIV Pre-exposure Prophylaxis (PrEP) to seek further information regarding its cost-effectiveness," a PBAC outcomes report said.

"Specifically the Committee requested additional analyses considering alternative uptake scenarios where the extent of uptake is reduced and use is limited to medium and high risk individuals, and varying the tenofovir with emtricitabine price."

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Truvada has been listed on the PBS for people who have already contracted HIV, but not as a preventative drug.

While the drug has previously been approved by the Therapeutic Goods Administration for treatment use in Australia and is currently being used in several trials across the country for people at high risk of contracting HIV, the PBAC claimed it would only see a taxpayer subsidy for Truvada on the PBS as appropriate if it were made available as a preventative drug for "individuals at high and medium risk of infection".

The PBAC also raised concerns over the proposed costliness of the drug if it were to be listed on the PBS at the price Gilead Sciences and Mylan Australia proposed, labelling it as "unacceptably high".

"The PBAC noted that the submission estimated annual expenditure exceeding $200 million per year in five of the six years of the estimates and considered the opportunity cost was unacceptably high at the proposed price," the report said.

The drug has been hailed as the silver bullet in the fight against HIV and three variant brands of the drug, sponsored by Gilead Sciences and produced by Mylan Australia, are currently listed on the PBS as treatment for people who have already contracted the disease.

Different studies have found PrEP could have an effectiveness rate of stopping HIV infections upwards of 90 per cent, however those individuals who are yet to contract HIV remain faced with exorbitant prices for the drug or difficult entry pathways into trials around the country.

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Around 8,000 people are currently enrolled in expensive trials of the drug around the country.

In response to Friday's deferral, the Australian Federation of AIDS Organisations has said it is "deeply frustrated" with the stalling of PBS negotiations.

"HIV will be needlessly transmitted while we wait for equitable and affordable access to PrEP," the organisation's CEO, Darryl O'Donnell said in a statement.

"Without access to PrEP, Australia will not achieve its target of ending HIV transmission by 2020.

"With Truvada now off patent, there's no reason PBAC shouldn't be able to negotiate a fair and reasonable price."

If the deferred recommendation of the drug comes back positive, the drug will still need to go through price negotiations, quality and availability checks and then be approved by the Turnbull government.

The deferral also comes after Federal Opposition leader Bill Shorten wrote to Prime Minister Malcolm Turnbull in March, asking for the government to intervene and ensure PrEP is listed on the PBS, and to expand trials of the drug in Australia.

While around 8000 people are currently involved in PrEP studies and trials in several states, Shorten said he was concerned that there are many people not able to be enrolled in the trials and not able to access the drug.

"You would be aware that for HIV negative people who are at high risk of HIV, PrEP has been proven to be highly effective in preventing HIV transmission," he wrote at the time.

"Australia has a proud history in HIV care, treatment, research, and prevention. Our response to the AIDS epidemic in the 1980s brought our public health response into the mainstream and changed practice around the world. From our perspective, better access to PrEP is the next phase in this public health response and a critical component of getting to zero, along with regular testing and Treatment as Prevention (TasP)."